1. Field
The present inventive concepts relate to semiconductor devices, and more particularly, to semiconductor devices that employ a high-k dielectric film.
2. Description of the Related Art
As the feature size of a MOS transistor is reduced, the gate length and channel length are likewise reduced. Accordingly, it is necessary to reduce a thickness of a gate insulating layer to increase capacitance between the gate and the channel and to improve operating characteristics of the resulting MOS transistor.
However, as the thickness of a silicon oxide layer, or silicon oxynitride layer, which are materials that are primarily used as a gate insulating layer, is reduced, certain physical limitations can manifest themselves which adversely affect the electric properties of the resulting device. That is to say, in a case wherein the silicon oxide layer is formed too thin, direct tunneling current can be increased, resulting in increased leakage current between the gate and the channel and, therefore, increased power consumption.
Therefore, in order to replace the conventional silicon oxide film, research into a high-k dielectric film having a high dielectric constant is being actively conducted. Such a high-k dielectric film can reduce leakage current between the gate and the channel while permitting a relatively thin geometry.